1. Field of the Invention
The present invention relates generally to the recording of data onto optical media, and more particularly to a method for formatting and initializing re-writable optical media to provide user access to the media after only a short preparation time, and to provide for data integrity during the format and initialization operations, and during the life of the media.
2. Description of the Related Art
When recording data to optical media, a user typically provides a blank optical media for recording, selects a plurality of files from a source or plurality of sources, and executes a recording function. The selected files can be of any type including audio files, video files, photographic files, data files, program application files, and the like. The recording function is typically executed by use of an optical media recording program which accomplishes such tasks as mapping out precise locations of source files, determining size of source files, mapping out a precise target destination for the selected files, calculating a theoretical transfer rate for reading the file from a source and recording the file to a destination, identifying those files that will be cached and those files that will be recorded directly from source to destination, performing necessary file formatting as required, and burning the selected files to a destination optical media.
Before any of the above functions can occur, however, the target optical media must be properly formatted. Generally, formatting includes defining a file system and structure for writing data to a media, or for simple audio recording, defining a generic structure. Although different types of data require different types and levels of destination media formatting, the process of formatting re-writable optical media has failed to keep up with basic user demand for simple and efficient methods for rapidly formatting and initializing optical media.
Typically, a user must spend from 30 to 50 minutes in preparing re-writable optical media for recording data files. Assuming compliance with such standards as ISO9660 and Universal Disc Format (UDF™), preparation of re-writable optical media for recording data files requires at least writing to the entire disc, and then, for optimum preparation, verification by reading back each block. In the remaining document, reference to “UDF” shall be understood to be with reference to registered trademark UDF™. Verification of user data recorded to the media after formatting only occurs upon reading data back from the media. If a problem occurs but is not detected during the write process, the user's data is already lost by the time the problem is eventually discovered.
FIG. 1A shows a block diagram 10 of a typical formatted re-writable optical media according to the UDF standard. Block 20 is the Lead In area, block 22 is the UDF file system, and block 23 is an area of null data. Null data consists typically of 0's written to the disc specifically for the purpose of formatting. Block 24 represents the UDF area reserved for redundant file system information and possibly for sparing purposes, and block 26 represents the Lead Out area. The structures shown in block diagram 10 are well known, and represent a typical UDF formatted media. FIG. 1A is representative of a formatting structure that, in prior art, must be accomplished before data is recorded to re-writable optical media, and such formatting typically takes from 30 to 50 minutes to complete. Generally, no other processes or operations may be conducted with the optical media once the formatting has been initiated and until the formatting is complete.
One prior art solution to the amount of time that is required for media formatting has been the manufacture and sale of pre-formatted media. The pre-formatting, or formatting of the re-writable optical media prior to the sale or distribution to a user, continues to take the aforementioned 30–50 minutes, but is accomplished during the manufacture of the media. Pre-formatted re-writable optical media are simply formatted during manufacture, and the cost of formatting during production is passed on to the user. Further, a typical user is easily confused if not skilled enough to know, for example, that data is commonly recorded in UDF format, but audio is not. If a user desires to record audio files, then a UDF-formatted disc will indicate to the recording system that the media is “full”. The recording system would then require that the media's pre-formatting be erased in preparation for audio recording.
Another prior art solution has been to utilize programming options described in the UDF specification. One such option is the “grow” format command defined in the MMC specification (SCSI-3 Multimedia Commands (MMC), published by the American National Standard of Accredited Standards Committee X3, Publication No. ANSI X3.304:1997, and other similar or related documents). The “grow” format command is designed for use to incrementally format a partially formatted media, and provides a reasonably rapid method of saving of files to a formatted area. Once the formatted area of the media has been filled, however, the process slows down dramatically, if supported at all. Many currently available media recording devices do not support the method prescribed by the “grow” format command, which further requires a number of programming or implementation steps well beyond the level of skill of the typical user.
Yet another prior art method of reducing the time required for re-writable optical media formatting has been a hardware solution. The hardware solution implements a rapid format technique allowing a user to write to media in just a few minutes after initiation of the rapid formatting. The hardware solution generally utilizes the UDF format, and proceeds to incrementally initialize whole sections of media while allowing a user to write to those sections that have been initialized. While the total time to format optical media may remain approximately the same as described and known for other methods of media formatting, the hardware-implemented rapid formatting provides the ability to write to the media before the formatting of the entire disc has been completed. So long as the user leaves the optical media in the hardware device capable of the hardware rapid formatting, the user can write to those portions of formatted media, as they become available.
FIG. 1B shows a block diagram 15 of a typical prior art rapidly formatted re-writable media using a hardware-implemented rapid formatting process. Block 30 represents a Lead In area, and block 32 represents the UDF file system. The Lead In area and the UDF file system shown in blocks 30 and 32 are substantially identical to the Lead In area and UDF file system shown in blocks 20 and 22 of FIG. 1A. In FIG. 1B, the UDF file system shown in block 32 is followed by an uninitialized area represented by block 34. The uninitialized area 34 represents an area of the media between the Lead In 30 and the Lead Out 40 that has never been written to or otherwise formatted. The uninitialized area 34 will be formatted and written to in the process of the media formatting, but the initial structures shown in FIG. 1B allow the media to be accessed with a system incorporating the hardware implementing the rapid formatting.
The uninitialized area 34 is followed by an area of null data 36, the UDF redundant file system information and sparing region 38, and the Lead Out area 40. Because a section of the media remains uninitialized 34, the Lead In 30 lacks an accurate reference to point to an exact location for the Lead Out 40. The null data block 36 ensures that devices implementing a seek-calibration process as part of the spinning up of a disc have adequate formatted space in and near the Lead Out 40 for the seek calibration process. In substantially all other respects, the UDF redundant file system information and sparing region 38 and the Lead Out 40 are the same structures as those described in FIG. 1A at blocks 24 and 26.
As illustrated in FIG. 1B, the hardware-implemented rapid formatting creates a formatted re-writable media that looks and operates similar to the typical UDF formatted media. When the hardware-implemented method is initiated, the Lead In 30, UDF file system 32, a small amount of null data 36, the file system information and sparing region 38 and the Lead Out 40 are written and verified. Once these structures are established and verified, the media appears as a formatted media, and can be written to and verified as any other media might be. So long as the media remains in the hardware device capable of implementing the hardware-implemented formatting, the remainder of the uninitialized area 34 is formatted in whole sections, during which time a user can access and interact with those sections of the media that have been formatted. As each whole section of media space is written and verified, that section becomes available for use as a formatted section of media. The process of formatting sections of media continues and allows use of those sections of media that have been formatted while the formatting is proceeding. This is true only as long as the media remains in the device that initiated the formatting, or is inserted into another device capable of performing the hardware-implemented rapid formatting.
If the media is ejected from the formatting device prior to completion of the formatting of the entire media, it can be inserted into another device, but there are limitations on its use. If the other device into which the media is inserted is not capable of a hardware-implemented rapid formatting of media, the media can only be accessed in read-only mode. Essentially, the media presents itself as having a closed session of data written thereon, and therefore can be accessed for reading, but not for writing or completion of the formatting process.
Another limitation of the prior art formatting process is that although many formatting process applications utilize some form of defect management in the initial formatting of a media, there is no known prior art method of defect management of media during its useful life. By way of example, the UDF specification defines a sparing table to be used for re-writing data that was discovered to contain errors during the verification process, and the process of implementing the sparing table is known in the art. The UDF specification does not, however, define an area or process for defect management that includes periodic verification of data after its initial writing to the optical media.
In accordance with the above, what is needed is a method and system for the formatting and initialization of media which allows user access to media after only a short preparation time, allows full read and write capabilities during the initialization process, provides data integrity during the initialization and during the life of the media, allows a user to eject the media during the initialization and have the initialization continue upon media reinsertion, and uses an incremental initialization method to allow partially initialized media to be readable and writable by a plurality of systems and software applications.